In recent years, there has been widespread use of a cloud service, such as an IaaS (Infrastructure as a Service) cloud service, that provisions a virtual resource of a computer system to a user. By subscription with a service provider, a user can use a virtual resource on demand, such as a virtual server, a virtual network, a virtual router, a virtual storage, or a virtual load balancer. There is for example a cloud service such as Amazon Web Services (registered trademark, http://aws.amazon.com/ec2). By causing middleware, such as an OS (Operating System), a DB (DataBase), a Web, and an electronic mailer, to run on a virtual resource, a user can build their own server without having to prepare a physical hardware device by themselves.
There has also been widespread use of open-source software for implementing IaaS. For example, there is provided a commercial cloud service based on open-source software called OpenStack (registered trademark). There is for example a commercial cloud service such as Rackspace (registered trademark, Public Cloud Powered by OpenStack, http://www.rackspace.com/cloud/).
Under such circumstances, according to classifications by provisioning method, a virtual server provided to a user by a cloud service on the market is mainly a virtual server which is a server with many CPU cores (many core CPU) virtualized using a hypervisor such as a Xen or a KVM (Kernel based Virtual Machine). A hypervisor however has a disadvantage of large overhead in the virtualization processing. In addition, there is a container-type virtual server (referred to as a container hereinbelow) with low performance degradation and a bare-metal physical server (referred to as a bare metal hereinbelow) involving no virtualization. Meanwhile, according to classifications by computational resources, there is not only a typical server having a CPU but also an FPGA (Field Programmable Gate Array) server optimized for a particular computation logic. An example thereof is a Bing Search server by Microsoft Corporation. There is also a new service provider that mounts a GPU (Graphical Processing Unit) of a typical client PC onto a cloud server to provide a server with high image processing capability as a cloud server. An example of such is a GPU instance server by Amazon Web Services.
Further, according to the classifications by provisioning method, there are block storage and object storage as virtual storage provided to a user. Further, according to classifications by storage resource, provisioning mainly conducted so far uses an HDD-based dedicated storage (e.g., VNX by EMC Corporation) to cut out virtual volumes and provide them to users. Meanwhile, some service providers have started to provide, as a virtual volume, an SSD, which has higher random IO (Input Output) performance than an HDD, or a hybrid storage of an SSD and an HDD. For example, Yahoo (registered trademark) uses a hybrid storage by Nimble Storage for its cloud storage. Further, a distributed storage such as Ceph or Swift is used for users that opt for low prices. An example of such is Konoha by GMO CLOUD K.K.
As described thus far, there are various virtual resources used in cloud services and various methods for provisioning the virtual resources. Thus, when a user selects a proper virtual server or the like according to the user's purpose of use, the performance of IaaS presumably improves, enhancing the user convenience. In a conventional cloud service, however, a virtual resource is selected from ones of the same model, and this makes it difficult to provide a proper virtual resource meeting the individual requirements of each user. For this reason, a user themselves needs to design a proper server configuration according to their functional requirement and performance requirement and then validate the performance of the server configuration, which requires high level of technical knowledge and effort.